ci: add .gitea folder

.gitea/workflows/ci.yaml

@@ -0,0 +1,17 @@
+name: Continuous Integration
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  lint_n_build:
+    runs-on: self-hosted
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-tags: true
+      - run: shellcheck files/sbin/certbot_renew
+      - run: make tarball
+      - run: rpmbuild -ba "$(make name).spec"